Effect Of Galvanic Vestibular Stimulation On Locomotion Task In Unilaterally Labyrinthectomized Rats

Effect Of Galvanic Vestibular Stimulation On Locomotion Task In Unilaterally Labyrinthectomized Rats
Dr. Moslem Shaabani1 , Dr. Yones Lotfi1,Dr. Seyed Morteza Karimian2
1 Audiology department, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
2 Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran

Background: Current experimental research on the therapeutic effects of galvanic vestibular stimulation (GVS) has mainly focused on neurodegenerative disorders. However, it primarily stimulates the vestibular nuclei and could be potentially effective in decreasing imbalance between them in the case of unilaterallylabyrinthectomized (UL) rats.

Objectives: Could the short-term GVS intervention be effective in reducing imbalance symptoms in the UL models?

Methods: Forty male Wistar rats (180-220 g) were used in 4 groups of 10: control, sham, and right-ULs

. The UL models were prepared by intratympanic injection of sodium arsanilate. GVS protocols were implemented 30 min/day and continued for 14 days via subcutaneous-mastoidal electrodes. Functional recovery was assessed by several postural-tests including support surface, landing and air-righting reflexes, and rotarod procedure. Immunohistochemistry were performed on ipsi- and contralateral medial vestibular nuclei (MVN) using bromodeoxyuridine (BrdU), as a marker of cell proliferation.

Results: Behavioral tests showed significant functional recovery of GVS-induced groups compared to sham group. BrdU-labeled cells were significantly higher in the ipsilesional MVN of both GVS-induced groups compared to control and sham groups and also to the contralesional side.

Conclusion: Coordinated findings of behavioral and immunohistochemical inspections can confirm the effectiveness of GVS in accelerating dynamic vestibular compensation. This could be explained by neuronal reweighting in vestibular nuclei and its consequences on their motor outputs. Therefore, GVS could be promising for rehabilitating the patients with unilateral vestibular weakness and for designing vestibular-prosthesis.